Current environmental concern from the danger of mercury pollution, has drawn remarkable efforts toward developing analytical methods for this metal. To determine the levels of mercury in our environment, very sensitive, as well as selective methods, must be employed. For example, the concentration of mercury in sea water can be as low as 2.times.10.sup.-12 M. As a result, most known methods require a preconcentration step. On the other hand, some samples need a pretreatment step to separate mercury from other interferences due to low selectivity of the applied method. These requirements substantially increase the time of analysis. In addition, and as a consequence of these low levels, the analyst encounters problems that influence the reliability of the results, such as sample preservation and contamination from reagents.
Mercury is one of the elements which has been concentrated and determined electrochemically on modified electrodes. One of the most sensitive electroanalytical techniques. i.e. anodic stripping voltammetry (a.s.v.) has been successfully applied to determine 10.sup.-9 M [Gao, Z., Li, P., Zhao, Z. Microchem. J. 43, 121-132 (1991)] and 5-10.sup.-11 M [Liu, K., Wu, Q., Liu., H. Analyst 115, 835-837 (1990)] of mercury using modified electrodes. Nevertheless, laborious preparation and conditioning of electrodes, synthesis of organic reagents and insufficiently high selectivity have discouraged the wide application of a.s.v. for the routine determination of mercury.